Optical imaging in an ocean environment is severely degraded in range and in resolution by distortions introduced by intervening media. Phase conjugation is a nonlinear optical technique that can correct media-induced distortions. This technique requires the high energy densities and coherence of laser radiation. Degenerate four-wave mixing in photorefractive crystals, such as barium titanate, can provide either externally pumped or self-pumped realizations of phase conjugation. The primary limitations in the application of the technique are the formation time of the corrected (i.e., phase conjugate) image and the amount of optical power required to form the image. The effectiveness of optical phase conjugate image correction was investigated for distortions due to (1) static variations in the refractive index, (2) temporal variations in the refractive index, and (3) an air-water interface. Fundamental issues related to the ability to correct for real time fluctuations and to the laser power requirements of the system were studied. We discuss the capabilities of phase conjugation to correct environmentally induced optical distortions in real time.